/*-*-mode:c++;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8-*-│
│ vi: set et ft=c++ ts=2 sts=2 sw=2 fenc=utf-8                             :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2025 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/nexgen32e/crc32.h"
#include "libc/testlib/testlib.h"

#define POLY 0xedb88320

uint32_t crc32z(uint32_t init, const void *data, size_t size) {
  static struct {
    bool once;
    uint32_t tab[256];
  } crc32;
  if (!crc32.once) {
    crc32init(crc32.tab, POLY);
    crc32.once = 1;
  }
  size_t n = size;
  uint64_t h = ~init;
  const unsigned char *p = (const unsigned char *)data;
  for (size_t i = 0; i < n; ++i)
    h = h >> 8 ^ crc32.tab[(h & 0xff) ^ p[i]];
  return ~h;
}

TEST(crc32, test) {
  ASSERT_EQ(crc32(0, "hello", 5), crc32z(0, "hello", 5));
}
